In Excel, the FLOOR function returns a number rounded down based on a multiple of significance.
The syntax for the FLOOR function is:

FLOOR( number, significance )

number is the number that you wish to round down.

significance is the multiple of significance that you wish to round a number to.

create function floor(@number decimal(16, 2)

, @significance decimal (16, 2))

returns decimal(16,2)

as

begin

       return   @number - (@number % @significance)

end

go